In packaging operations, it is common to place multiple layers of items on top of a pallet.
Typically, a separation or cover sheet made of paper or another suitable material, known as a liner sheet or a “slip sheet”, is placed on top of the pallet, underneath the first layer of product, in order to separate the product layer from the pallet. Since pallets are generally constructed from wood and reused, the slip sheet prevents splinters and other particles from coming in contact with the product and contaminating it. In addition, in some cases additional slip sheets may be placed between layers, or between groups of layers, to improve the stability of the stack of items on the pallet.
As can be imagined, the speed at which items can be stacked onto a pallet has a significant influence on productivity.